Undeserved accidents ?

[Amanda]

Hi to you medical staff.

I have a question about those "undeserved" Deco Accidents. What I call 'undeserved' is:

-the diver was under the safety curve on the dive tables

-the diver was not tired, drunk or sick when diving

- the dive was a non-deco one

-the diver was not too old / too fat / unfit etc

I hope my english is good enough for you to understand what types of accidents I am talking about- those who no-one understands.
What percentage of the whole number of deco accidents do they represent?
Just curious...

Please ask fot clarifications if that's not understandable

 

[MikeFerrara]

Statistical reality, dehydration and lots of little mistakes that just add up to sloppy diving.

On a side note...I wonder who is cutting it closer, the rec diver who ends the dive before their computer shows "red" but does this several times per day throughout their vacation week and then flies home or a technical diver who though exceeding "no-stop" limits does a good job of decompressing with the right gasses then rests on the surface (still breathing those gasses) and probably only does one of those dives per day.

 

[Dr Deco]

Dear Amanda:

Undeserved Hits

In a sense, almost all hits are “undeserved.” By this I mean, if you follow the table or the meter, you should not experience a problem with DCS. That is what we get in the laboratory - none, nada, nichts. But some do, so what is the story here?

Table Testing

When tables are tested in a laboratory (e.g., the PADI Recreational Dive Planner), there were not any hits and the Doppler bubble scores were low. No one should have a problem with this table, and especially no incidences of neurological DCS . This is not really the experience in the field. It is not really known, but that won’t stop me from venturing an answer.

I believe that it is traceable to how divers use them in the field. They go through the litany of Dr Deco’s No-Nos. Among these we have

• climbing back onto the boat with all of your heavy gear,
• lifting heavy gear on the boat,
• climbing ladders or performing strenuous activity on board,
• sleeping during the interdive interval and slowing nitrogen washout,
• being very active on the bottom during nitrogen uptake.

To this could be added dehydration, and not being in good physical shape.

However, physical conditioning is somewhat accounted for in the test population of the subjects during table testing.

Testing of Products

Many of these ideas are hypotheses from my decades of research in barophysiology. Much is untested, as manufactures would rather pass kidney stones than the needed dollars to test the products.

Dr Deco :doctor:

 

[Amanda]

Thanks for the answer...

I don't understand why the tables don't take into account that a diver is more or less obliged to go back on the boat, undo his/her gear etc... this implies a tiny little effort that, as you said, can be important in incidents, or even accidents.

 

[Dr Deco]

I believe that the answer is that this problem has only recently been found. It was found through studies related to decompression in microgravity.

This is a "spin off" of the space program.

Dr Deco:doctor:

 

[annie]

I would be curious to know how many cases of the the bends occurred after a correct dive profile - within the tables or computer or whatever.
In October a guy I was diving with got bent after a perfect dive profile (he exerted himself during the dive) and according to the people there at the time, most cases of the bends turn out to be the cause of contributing factors . . .I don't think many divers realise how much of an impact these factors can have.

 

[Diver0001]

Dr Deco once bubbled...
I believe that the answer is that this problem has only recently been found. It was found through studies related to decompression in microgravity.

This is a "spin off" of the space program.

Dr Deco:doctor:

If you read the tek-lists you will get the impression that most (if not all) undeserved hits are related to PFO's. Any basis in fact for this?

R..

 

[leadweight]

Watching from my safety stop, there seems to be a large variation in effort among different divers climbing back on the boat. Some seem to time it just right and others struggle. It would seem that someone who is overweight would have to work a lot harder to climb back on the boat. I wonder how much of a factor obesity would be in this context as distinct from issues regarding nitrogen uptake in fat tissue.

 

[Big-t-2538]

annie once bubbled...
I would be curious to know how many cases of the the bends occurred after a correct dive profile - within the tables or computer or whatever.
In October a guy I was diving with got bent after a perfect dive profile (he exerted himself during the dive) and according to the people there at the time, most cases of the bends turn out to be the cause of contributing factors . . .I don't think many divers realise how much of an impact these factors can have.

Did he do a safety stop?

 

[annie]

Yes I saw him do one, although I didn't time him (not my buddy) afterwards he swore he'd done 3 mins at 5m. It certainly wasn't any more than that - I remember thinking at the time that he could have hung there a bit longer just to be conservative (and it was really nice too).